Effect of the equilibrium pair separation on cluster structures

TL;DR

This study introduces a versatile pair potential allowing control over cluster structures by varying equilibrium pair separation, revealing how different sizes and potential shapes influence the stability of various cluster geometries.

Contribution

A new pair potential model is proposed that can stabilize different crystal structures and systematically study the effect of equilibrium pair separation on cluster morphology.

Findings

Small clusters are unaffected by potential details.

Large clusters favor decahedral and close-packed structures with larger pair separation.

Intermediate separations favor icosahedral structures.

Abstract

A simple pair potential, which equilibrium pair separation can be varied under a fixed interaction range, has been proposed. The new potential can make both face-centered-cubic(fcc) and body-centered-cubic(bcc) structure stable by simply changing one parameter. To investigate the general effect of the potential shape on cluster structures, the evolution of cluster structures is calculated for different equilibrium pair separations. The small size clusters($N<25$), which adopt the polytetrahedra, are almost independent on the details of the potential. For the large size clusters($25<N<150$), the potential with large equilibrium pair separation trends to stable decahedra and close-packed structure, disordered clusters appear for the potential with small equilibrium pair separation, while for the middle range of equilibrium pair separation, the icosahedra are dominated.